Inkjet printing systems frequently make use of printheads mounted to a carriage which is moved back and forth across a print media, such as paper. As the printhead is moved across the print media, control electronics activate an ejector portion of the printhead to eject, or jet, ink droplets from ejector nozzles and onto the print media to form images and characters. An ink supply provides ink replenishment for the printhead ejector portion.
Some printing systems make use of an ink supply that is replaceable separately from the printhead. When the ink supply is exhausted, the ink supply is removed and replaced with a new ink supply. The printhead is replaced at or near the end of the printhead life and not when the ink supply is exhausted. When a printhead is capable of reuse with a plurality of ink supplies, it is usually referred to as a xe2x80x9csemipermanentxe2x80x9d printhead. This is in contrast to a disposable printhead, that is replaced with each container of ink.
A significant issue with semipermanent printheads is the ability to keep air from entering the supply, especially over long periods of time. Air present in a printhead can interfere with the quality of the printing. Also, air negatively affects the ink printhead of the printer. By way of example only and not by way of limitation, air decreases the reliability of the printhead. In printheads that utilize a regulator to control the flow of ink into the printhead, an accumulation of air in the printhead will cause the printhead to fill up with air, thus resulting in a premature failure of the printhead.
Air accumulates during printhead life from a number of sources, including diffusion from the outside atmosphere into the ink supply. One solution to the air accumulation problem has been the use of disposable printheads. The geometry or size of an ink container associated with a printhead can be chosen to keep air accumulation below a critical threshold. When the amount of ink is small, this increases the cost of printing by requiring frequent printhead replacement. Alternatively, the ink container can be made larger to reduce the frequency of printhead replacement. However, large ink containers become problematic when the printing application is a compact desktop printer. An example of a system utilizing a disposable printhead, wherein a large ink supply is replaced each time the printhead is replaced, is described in U.S. Pat. No. 5,369,429.
Another solution to the air accumulation problem has been the use of air purge mechanisms to make semipermanent printheads viable. An example of an air purge approach is described in U.S. Pat. No. 6,152,559. Issues with purging systems include the added printer cost for the purge mechanism, the reliability problems associated with accommodating the ink that tends to be purged out with air, and the stranding of air in ink ejectors of the printhead, and an increase in maintenance requirements.
In short, there is a need for a low cost, high air barrier ink supply that is suitable for a desktop printer.
Briefly, the present invention comprises, in one embodiment, an ink supply for a printing system comprising a chassis with at least one aperture extending therethrough, a bag comprising material that is resistant to air diffusion, wherein the bag is attached to the chassis to allow ink communication from the bag through the aperture in the chassis, and at least one air barrier insert with an aperture therethrough positioned in the at least one aperture of the chassis.
In a further embodiment of the present invention, there is provided an ink supply for a printing system comprising a chassis, wherein the chassis comprises first and second protrusions, and wherein an aperture extends through each of the protrusions to allow fluid communication therethrough, a bag, wherein the bag is attached to the chassis so that at least a portion of the first protrusion is surrounded by the bag, at least one air barrier insert, wherein the air barrier insert is located in the aperture, a septum, wherein the septum is located in the air barrier, a film, wherein the film is attached to the second protrusion and covers the aperture in the protrusion, and, a shell, wherein the shell extends around at least a portion of the bag.
In a further embodiment of the present invention, there is provided a method of printing, comprising the steps of obtaining a printer utilizing a replaceable ink supply, wherein the ink supply comprises a chassis, wherein the chassis comprises a first and second protrusion, and wherein an aperture extends through each of the protrusions to allow fluid communication; a bag, wherein the bag is attached to the chassis so that at least a portion of the first protrusion is surrounded by the bag; at least one air barrier insert, wherein the air barrier insert is located in the aperture; a septum, wherein the septum is located in the air barrier; a film, wherein the film is attached to the second protrusion and covers the aperture in the protrusion; and a shell, wherein the shell extends around at least a portion of the bag; and printing from the printer.
In a further embodiment of the present invention, there is provided a printer, comprising an ink supply station comprising a needle, adapted to interface with a replaceable ink supply, wherein the ink supply comprises a chassis, wherein the chassis comprises first and second protrusions, and wherein an aperture extends through each of the protrusions to allow fluid communication therethrough; a bag, wherein the bag is attached to the chassis so that at least a portion of the first protrusion is surrounded by the bag; at least one air barrier insert, wherein the air barrier insert is located in the aperture; a septum, wherein the septum is located in the air barrier; a film, wherein the film is attached to the second protrusion and covers the aperture in the protrusion; and a shell, wherein the shell extends around at least a portion of the bag.
In a further embodiment of the present invention, there is provided a method of making ink supply comprising attaching a chassis to a bag for containing ink, wherein the chassis comprises a first and second protrusion, and wherein an aperture extends through each of the protrusions to allow fluid communication, and wherein the bag is attached to the chassis so that at least a portion of the first protrusion is surrounded by the bag; inserting at least one air barrier insert into the chassis, wherein the air barrier insert is inserted in the aperture; inserting a septum into the air barrier; attaching a film to the second protrusion so that the film covers the aperture in the protrusion; and attaching a shell to the chassis so that the shell extends around at least a portion of the bag.